For the second time in three weeks, EU leaders will meet to discuss how to stem the tide of refugees making their way to Europe, amid fears the worsening conflict in Syria will drive another wave of people towards their continent.
More than 590,000 migrants and refugees have reached Europe via the Mediterranean Sea this year, while some 3100 have died trying to do so, according to the International Organisation for Migration.
It is the largest population movement Europe has had to grapple with since World War II.
More than half of those arriving are from Syria, according to the UN refugee agency UNHCR.
Almost five years of conflict have left the Middle Eastern country in tatters and displaced more than half of its pre-war population of 22.4 million.
The recent start of Russian airstrikes in the country has complicated the situation even further and raised the spectre of many more Syrians leaving to seek protection elsewhere.
"We should be talking about millions of potential refugees trying to reach Europe from Syria alone - not to mention Iraq, Afghanistan, Eritrea and other places," EU President Donald Tusk said after the bloc's 28 national leaders held an extraordinary summit last month.
"It is clear that the greatest tide of refugees and migrants is yet to come," he said.
"Therefore we need to correct the [European] policy of open doors and windows."
The EU is obliged under international law to offer asylum to those who arrive on its territory qualifying for protection.
EU leaders will meet on Thursday (local time) and call for officials to "work speedily on adopting a joint action plan with Turkey as part of a comprehensive co-operation agenda based on mutual commitments and delivery", according to a working draft of the summit statement seen by dpa.
Their two-day meeting will also feature discussions on another political minefield - Britain's planned referendum on EU membership and its bid to win concessions from other member states before the poll is held.